Michel Giguere

Increase in plasma high-density lipoprotein concentration following complete androgen blockage in men with prostatic carcinoma

There is evidence that endogenous estrogens have a positive effect on plasma high density lipoprotein (HDL) concentration, whereas the relation between HDL and male sex hormones is unclear, since both positive and negative effects have been reported. This study examined the effects of LHRH agonist in combination with an antiandrogen on plasma lipids and lipoproteins in 17 elderly men with prostatic carcinoma. Subjects were examined prior to and after therapy at 4-week intervals up to 16 weeks. Prior to therapy, their lipid and lipoprotein profiles were not significantly different from a control group composed of individuals of similar age and living in the same community area. Following therapy plasma levels of testosterone and dihydrotestosterone were markedly decreased (above 90%) and their residual activity neutralized through effective use of an antiandrogen. Plasma estradiol decreased between 65% and 85% and the concentration of cortisol was unaffected. The very low density lipoprotein (VLDL) apo-B decreased and low density lipoprotein (LDL) apo-B increased; thus, no change was observed in the total plasma apo-B levels. Total plasma cholesterol increased by 6% (baseline v peak values, mg/dL, mean +/- SEM; 219 +/- 9 v 233 +/- 9, P less than 0.05) due to a significant rise in HDL cholesterol concentration (45.5 +/- 2.8 v 56.5 +/- 3.6, P less than 0.01). Both VLDL and LDL cholesterol levels remained unchanged. The mean elevation of 21% in HDL cholesterol was accompanied by a significant rise in HDL apo-A concentration (161 +/- 6 v 193 +/- 10, P less than 0.01), thus suggesting an increase in HDL mass and/or particle number.(ABSTRACT TRUNCATED AT 250 WORDS)

Combination therapy with flutamide and castration (LHRH agonist or orchiectomy) in advanced prostate cancer: A marked improvement in response and survival

Eighty-seven previously untreated patients with clinical stage D2 (bone metastases) prostate cancer have received the combination therapy with a pure antiandrogen and an LHRH agonist (or orchiectomy) as first treatment in a multicentre study for up to 34 months (average = 16.2 months). A positive objective response assessed according to the criteria of the US NPCP has been observed in all cases. Pain disappeared in all patients within 1 month and performance become normal in all (including 2 bedridden patients) within 4 months. Progression of the disease after a period of remission has been observed in only 8 patients. Only one patient has died from prostate cancer while 3 have died from other causes. The probability of continuing response and survival at 2 years for the patients who receive the combination treatment (Kaplan-Meiers method) is 81 and 91%, respectively. By contrast, in the randomized group who had orchiectomy alone, 4 of 7 have died from prostate cancer (P less than 0.05 as compared to combination therapy). In addition to a marked improvement in the remission rate and survival, combination therapy maintains a good quality of life, hot flashes and a decrease or loss of libido being the only side-effects.

Advantages of the combination therapy in previously untreated and treated patients with advanced prostate cancer.

In order to achieve a more complete blockade of androgens of both testicular and adrenal origin at the start of treatment, we have administered the pure antiandrogen Flutamide in association with orchiectomy (13 patients) or the LHRH agonist [D-Trp6]LHRH ethylamide (118 patients) to previously untreated patients with clinical stage D2 prostate cancer. The mean duration of treatment was 491 days (102-1208 days). The response was assessed according to the criteria of the U.S. National Prostatic Cancer Project. A complete response has been observed in 30 patients (23%) while partial and stable responses have been achieved in 50 (38%0 and 45 (34%) patients, respectively. A positive objective response has thus been observed in 125 of 131 patients (95%). Serum PAP became normal before 6 months in all except 8 (6.1%) of patients. Quite remarkably, 23 of 48 patients treated for 2 years (47.9%) have achieved a complete response. Of the 20 deaths, 12 (9%) were due to prostate cancer, while 8 (6%) resulted from other causes. The probability of continuing a positive response after 2 years of treatment (according to Kaplan and Meier) is 60% while the probability of survival at the same time interval is 89%. This survival should be compared to values of approx 50% achieved with previous treatments limited to inhibition of testicular androgen secretion or action. The present data demonstrate that the combined blockade of androgens achieved with Flutamide and castration provides an objective response in approx 95% of patients, and markedly prolongs the period of remission while the death rate within the first 2 years is lower than that obtained with previous treatments. The important prolongation of survival is achieved with an excellent quality of life. Two-hundred and three patients have clinical stage D2 prostate cancer previously treated by orchiectomy, estrogens or LHRH agonists alone received, at the time of relapse, the same combination therapy. Patients already castrated received only Flutamide while, for those previously treated with DES, the estrogen was replaced by the LHRH agonist [D-Trp6]LHRH ethylamide in association with Flutamide. Flutamide was given as additional medication to those already receiving an LHRH agonist alone. Complete, partial and stable objective responses assessed according to the criteria of the U.S. National Prostatic Cancer Project were obtained in 11 (5.4%), 17 (8.4%) and 38 (18.7%) patients, respectively, for a total objective response rate of 32.5%. Progression continued in 137 (67.5%) patients.(ABSTRACT TRUNCATED AT 400 WORDS)

Combination therapy with flutamide and castration (LHRH agonist or orchiectomy) in previously untreated patients with clinical stage D2 prostate cancer: Today's therapy of choice

One hundred and ninety-nine patients with clinical stage D2 prostate cancer who had not received previous endocrine therapy or chemotherapy were treated with the combination therapy using the pure antiandrogen Flutamide and the LHRH agonist [D-Trp6]LHRH ethylamide for an average of 26 months (3-59 months). The objective response to the treatment was assessed according to the criteria of the U.S. NPCP. There was a 5.7-fold increase (26.3 vs 4.6%) in the percentage of patients who achieved a complete response compared with the results obtained in five recent studies limited to removal (orchiectomy) or blockade (DES or Leuprolide) of testicular androgens. Only 12 of the 186 evaluable patients (6.5%) did not show an objective positive response at the start of the combination therapy compared with an average of 18% in the same five studies using monotherapy. The duration of response was also significantly improved in the patients who received the combination therapy while the death rate was decreased by approximately two-fold during the first 4 yr of treatment. In fact, while an approximately 50% death rate is observed at 2 yr in all studies using monotherapy, the same 50% death rate is delayed by 2 yr in the present study. It should be mentioned that at the time of relapse under combination therapy, the treatment is continued and, in addition, further blockade of adrenal androgen secretion is achieved with aminoglutethimide. The marked (5.7-fold) improvement in the rate of complete objective responses coupled with the three-fold decrease in the number of non-responders, the increased duration of the positive responses and the two-fold decrease in the death rate during the first 4 yr of treatment are obtained with the combination therapy using Flutamide and castration, thus improving the quality and duration of life with no or minimal side-effects. By blocking the androgen receptors in the prostatic cancer tissue, the antiandrogen decreases the action of the androgens of adrenal origin and thus inhibits the growth of a large number of tumors which, otherwise, would continue to be stimulated by the adrenal androgens left after medical or surgical castration.

Combination therapy with flutamide and [d-Trp6]LHRH ethylamide for stage C prostatic carcinoma

Sixty-seven previously untreated patients presenting with clinical stage C prostatic carcinoma with no evidence of distant metastases received combination therapy using the antiandrogen Flutamide and the LHRH agonist [D-Trp6]LHRH ethylamide for an average duration of treatment of 23.5 months. Only five patients have so far shown treatment failure with 91.8% of the patients still in remission at 2 years. Three patients have died from prostate cancer while three have died from other causes, 93.5% of the patients being alive at 2 years. Local control was achieved rapidly in all except one patient. Urinary obstruction and hydronephrosis were corrected in all cases. When comparing to recent data obtained after single endocrine therapy (orchiectomy or estrogens), or radiotherapy, the rate of treatment failure at 2 years is 3.5-fold lower after combination therapy (8.2%) than monotherapy (28.4%). The death rate at 2 years following start of the combination therapy is 6.5% while it is on average 22.2% (3.4-fold higher) in the studies using monotherapy (orchiectomy or estrogens) or radiotherapy. The present data suggest that treatment of prostate cancer with combination therapy before clinical evidence of dissemination of the disease permits a better response which is possibly explained, at least in part, by the lower degree of dedifferentiation and heterogeneity of the tumors.

Combination therapy with flutamide and castration (orchiectomy or LHRH agonist): the minimal endocrine therapy in both untreated and previously treated patients

Patients (154) with clinical stage D2 prostate cancer with no previous endocrine therapy or chemotherapy received the combination therapy with the pure antiandrogen Flutamide and the LHRH agonist [D-Trp6]LHRH ethylamide for an average of 22 months (3-49 months). The objective response to the treatment was assessed according to the criteria of the US NPCP. There was a 6.3-fold increase (29.2 vs 4.6%) in the percentage of patients who achieved a complete response as compared to the results achieved in five recent studies limited to removal (orchiectomy) or blockade (DES or Leuprolide) of testicular androgens. Only 4.5% of patients did not respond to the combination therapy as compared to an average of 18% by standard therapy. The duration of response is also significantly increased in the patients who received the combination therapy. The death rate was decreased by approximately 2-fold between 2 and 3 yr of treatment. The marked (6.3-fold) improvement in the rate of complete objective responses coupled with the 4-fold decrease in the number of non-responders, the increased duration of the positive responses and the 2-fold decrease in the death rate at 2-3 yr of treatment are obtained with the combination therapy using Flutamide and castration with no or minimal secondary effects.

Important Prognostic Value of Standardized Objective Criteria of Response in Stage D2 Prostatic Carcinoma

One hundred and eighty-six previously untreated patients with clinical stage D2 prostate cancer have been followed according to the criteria of objective response of the National Prostatic Cancer Project (NPCP). All patients received combination therapy with the antiandrogen Flutamide and the LHRH agonist (D-Trp6, des-Gly-NH2(10)]LHRH ethylamide (or surgical castration, 10 patients) as first treatment. Forty-nine patients (26.3%) achieved a complete response as best response while 56 (30.1%) and 69 (37.1%) patients had partial and stable responses, respectively, and only 12 patients (6.5%) did not respond to treatment. The median times required to achieve stable, partial and complete responses were 155, 183 and 401 days, respectively. The best response achieved has a major influence on the probability of continuing response and survival. While the 50% probability of continuing response is more than 3 years for the complete responders, it is reduced to 630 and 517 days for partial and stable responders, respectively. While the non-responders have a median life expectancy of 10.0 months, this value is increased to 30.3 and 37.8 months for the stable and partial responders, respectively. The best probability of survival is for the complete responders with a 95.9% probability of survival at 3 years. There is no significant correlation between the time required to achieve a best response (phase 1) and the duration of the response before progression occurs (phase 2) or the time between progression and death (phase 3) for any of the categories of responses. A longer period of time required to achieve a complete response is associated with a longer survival. When analysis is made, in an attempt to predict response, of the baseline characteristics of the patients before treatment, a low number of bone metastases and better performance status are associated with a greater chance of achieving a complete response while partial, stable and progression responses cannot be predicted from the baseline characteristics. The present data show the importance of standardization of the objective criteria of response to treatment in advanced prostate cancer. Thus, the patients who achieve a complete response have a much more favorable prognosis while partial and stable categories of response have a closely similar prognosis which is inferior to the complete responders. Moreover, the present data indicate that the stable category of response has an important prognostic value which is almost superimposable and not statistically different from the partial response in terms of duration of response and survival.(ABSTRACT TRUNCATED AT 400 WORDS)

Combination therapy in stage C and D prostatic cancer: rationale and five year clinical experience.

In 1941, Huggins and his colleagues discovered that testicular androgens exert a stimulatory effect on prostate cancer growth. Our group has made the key observations that the human adrenals, in addition to the tests, also secrete important amounts of androgens and cancer cells exhibit a marked heterogeneity of androgen sensitivity. In fact, human adrenals secrete large amounts of precursor steroids that are converted into active androgens in peripheral tissues (including the prostate), thus providing 40% to 50% of total androgens in adult men. The action of these androgens remaining after castration can be inhibited in prostatic cancer tissue by administering a pure antiandrogen that also decreases the local concentration of dihydrotestosterone (DHT). The castration levels of serum testosterone left in men after castration have an important stimulatory activity on the growth of androgen-sensitive normal as well as cancer tissues. Cancer cells have markedly different requirements for androgens. Some cell clones can grow in the presence of minimal amounts of androgens, requiring more complete androgen blockade and more potent antiandrogens for inhibiting growth. Among the compounds recommended as antiandrogens, the most unexpected finding is that many of them are devoid of any antiandrogenic activity. In fact, medroxyprogesterone acetate, chlormadinone acetate, and megestrol acetate have androgenic activity, but do not inhibit the peripheral action of DHT in prostatic tissue. These compounds should not be classified as antiandrogens. Cyproterone acetate, on the other hand, is a mixed agonist-antagonist. The only compounds showing pure antiandrogenic activity are Flutamide and its analogues.There is thus a need for a more complete blockade of androgens of both testicular and adrenal origins in order to exert a maximal inhibitory effect on cancer growth. We have therefore performed clinical studies in previously untreated stage D2 and C prostate cancer patients with the combination therapy using the LHRH agonist [D-Trp6, des Gly NH210] LHRH ethylamide and the antiandrogen Flutamide. There was a significant increase in patients with a complete response, as compared with studies limited to the removal or blockade of testicular androgens. There was also a significant decrease in the number of non-responders, an increased duration of positive response, and a decrease in the death rate. This was achieved with minimal or no side effects, thus preserving a good quality of life.